Related Clues:

• Johnson's publisher - look out for his name in Latin
• Watch out for the hole
• Look out for English nurse who's shed a couple of pounds
• Hollow in the earth
• Norris leaves carnivores in grotto
• Place studied by a speleologist
• Watch out! There's a great big hole!
• Underground space
• Pothole -- beware!
• Take care in underground passage
• Beware of schoolboys
• Large grotto
• Hollow Conservative greeting
• Beware of a dark place
• Bat's underground home